The invention relates generally to instrumentation for measuring acceleration in a gun-launched projectile, and more particularly to a fuse-mounted differential variable resistance transducer disposed aft of the simulated warhead.
Destruction of underground hardened targets may require deep penetration munitions. Such devices can include gun-launched projectiles. Tests to correlate penetration depth with deceleration of an instrumented shell into a simulated target may incorporate displacement sensors, such as accelerometers and proximity detectors. A Hall effect probe, which responds to Lorentz force reaction to a magnetic field perpendicular to the current flow, represents an exemplary proximity sensor without physical contact with a neighboring object. Further details on these principles can be found in http://hyperphysics.phyastr.gsu.edu/hbase/magnetic/hall.html.
In the presence of a magnetic field, the path of an electric current curves perpendicular to the magnetic field due to the Lorentz force producing an asymmetric distribution of charge density across the Hall effect probe or device that generates an electric potential. In response to voltage applied across two terminals of the Hall device, a third terminal provides a voltage proportional to the induced current. Hall devices have no mechanically moving parts and thus provide enhanced reliability in extreme environments, such as for projectiles subject to high accelerating and decelerating conditions.